A cadaver study evaluating intraluminal anomalies of the left common iliac vein.

OBJECTIVE: Intraluminal anomalies within the left common iliac vein, characteristic of iliac vein compression syndrome, are thought to result from compression by and pulsation of the overlying right common iliac artery. This cadaver study was designed to expand on the existing literature by surveying and photographing these spurs in addition to exploring whether certain factors, inherent to the cadaver, are associated with spur presence. METHODS: Dissection to expose the aorta, inferior vena cava, and common iliac arteries and veins was performed in 51 cadavers. The spinal level at which the iliac vein confluence occurred was noted. The point at which the right common iliac artery crossed the left common iliac vein was examined for plaque presence. The overlying arterial structures were then transected to expose the venous system. The inferior vena cava was incised to facilitate observation into the mouth and full extent of the left common iliac vein. Spurs were photographed and documented. Statistical analysis was conducted to determine whether sex, body mass index (BMI), plaque presence, or level of the iliac vein confluence are associated with spur presence. RESULTS: Spurs within the left common iliac vein were observed in 16 of 51 cadavers (31.4%). All spurs were located at the point that the right common iliac artery crossed the left common iliac vein. Using1 the classification system established by McMurrich, 67% of spurs (n = 10) were marginal and triangular; 25% (n = 4) were columnar. One marginal, linear spur (6%) and one partially obstructed spur with multiple synechiae (6%) were observed. Among this population, males were 73% less likely to have a spur (odds ratio, 0.269; P = .041). No significant relationship was found between plaque presence and spur presence (odds ratio, 0.933; P = .824) and no significant differences were noted between BMI and spur presence (χ2 = 1.752, P = .625). Last, a significantly greater percent of spurs was found within cadavers with an iliac vein confluence located at the L5/S1 disc space (χ2 = 9.650; P = .002). CONCLUSIONS: Study findings show that spurs are more common when the confluence of the common iliac veins occurs at a lower spinal level. The level of the iliac vein confluence may be important in identifying patients at increased risk of venous disease. The findings also suggest that plaque within the right common iliac artery and BMI display no distinct relationship with spur presence. Further investigation is needed to understand exactly what factors lead to spur formation.

Heparin-associated antiplatelet antibodies increase morbidity and mortality in hemodialysis patients.

BACKGROUND: Patients are frequently exposed to heparin during hemodialysis (HD) to prevent thrombosis of the extracorporeal circuit. Other groups with frequent heparin exposures have a high rate of development of heparin-associated antiplatelet antibodies (HAAb). We sought to define the prevalence of HAAb in HD patients and evaluate their effects. METHODS: A chart listing of all patients undergoing HD at our tertiary care institution during a six-year period was obtained. Charts of patients who tested positive for HAAb were reviewed. A cohort of randomly selected HD patients who tested negative for HAAb was analyzed as a control group. RESULTS: In our sample, 3.7% of HD patients were positive for HAAb. Morbidity, as defined by thromboembolic (TEC) or hemorrhagic complications, was higher in the HAAb-positive group compared with the control patients (60% vs 8.7%, P < .05), and the mortality rate (mortality directly related to TECs) was also higher in the HAAb-positive patients (28.6% vs 4.35%, P < .05). CONCLUSIONS: Contrary to reports of HAAb in patients undergoing HD without increased morbidity and mortality, we found significant increases in both morbidity and mortality. The elevated morbidity and mortality may represent ongoing endothelial and platelet activation from repeated heparin exposures. Reduced morbidity and mortality will likely require early recognition of HAAb and alteration of anticoagulation in HD patients.

Heparin-induced thrombocytopenia: twenty-nine years later.

OBJECTIVE: To determine the current frequency, types of patients, indications for testing, morbidity and mortality, and management of heparin-induced thrombocytopenia (HIT). METHODS: Between December 1998 and July 2001, the charts of 102 inpatients that tested positive for heparin-associated antiplatelet antibodies (HAAb) were reviewed. There were 33,941 inpatients, 10,348 of them having received unfractionated or low molecular weight heparins. HAAb were determined by platelet aggregometry. RESULTS: There were 58 males and 44 females with a mean age of 56 years. The majority (72%) of patients were admitted to a surgical service (23% were admitted to medicine, and 5% were admitted to obstetrics/pediatrics). Indications for testing included one or more low platelet counts (n = 51), unexplained arterial (n = 33) or venous (n = 6) thromboses, resistance to anticoagulation (n = 1), prior history of HAAb (n = 3), organ transplant (n = 17), or other indication (n = 4). The HAAb "patterns" were variable, with patients having antibodies only to bovine (n = 7) or porcine heparin (n = 5), bovine and porcine heparins (n = 17), enoxaparin (n = 3), fragmin (n = 7), or all 4 heparins (n = 43). The HIT-related mortality was 6.9%, and the morbidity was 30% with 19 arterial and 7 venous thromboses and 5 bleeding events. Management consisted of discontinuation of heparin in 95 patients. Twenty-five patients did not require continued anticoagulation. When needed, anticoagulation was continued with a direct thrombin inhibitor (n = 32), enoxaparin (n = 16), warfarin (n = 15), or aspirin (n = 7). Seven patients continued to receive unfractionated heparin (n = 4) or low molecular weight heparin (n = 3). CONCLUSIONS: HIT occurs in 0.99% of inpatients receiving heparin and remains an important nondiscriminatory contributor to their morbidity and mortality. Patients receiving any form of heparin who develop a decreasing platelet count, unexplained thrombosis, or resistance to heparin anticoagulation should be tested for HAAb. If HAAb are detected, patients must not receive the sensitizing heparin(s).

Intraoperative communication of residents with faculty: perception versus reality.

INTRODUCTION: During a surgical procedure, an attending may propose a surgical treatment that a resident believes is not the standard of care based on previous readings, discussions with other faculty, or experience. We hypothesized that resident disagreements over intraoperative management are common and are handled differently by residents than faculty members perceive. METHODS: Surveys were sent to 68 residents (82% response) and 45 faculty (91% response) in general surgery and seven subspecialties. Questions were asked to determine the frequency of disagreements and the differences in perceptions of how residents should act when they have disagreements over the intraoperative decisions of attendings. Significance was defined using Fisher's exact test at P < 0.05. RESULTS: Residents reported having major disagreements with faculty over intraoperative decisions as often as monthly (41%) or two to three times per year (37%). Estimates of the frequency of major resident disagreements did not differ between attendings and residents. Fewer residents felt comfortable asking the faculty to discuss their intraoperative decisions than was perceived by faculty members (41% vs 78%, P < 0.001). Residents at all levels are less comfortable than perceived by their mentors in discussing intraoperative decisions even when residents believe that patient injury may result. Residents felt that most of their disagreements occurred because of attending knowledge deficit, while most attendings attributed these differences to resident knowledge deficits. CONCLUSION: Residents frequently have disagreements with faculty over intraoperative management. Education to improve preoperative and intraoperative communication between surgical residents and faculty is needed.